1. Field of the Invention
The present invention relates to a substrate processing apparatus, a method of manufacturing a semiconductor device, and a ceiling insulating part.
2. Description of the Prior Art
Examples of substrate processing apparatuses include semiconductor manufacturing apparatuses, and examples of the semiconductor manufacturing apparatuses include vertical diffusion-CVD (chemical vapor deposition) apparatuses. In such a substrate processing apparatus, a heating device is used to heat a substrate.
Patent document 1 discloses an exemplary heating device which is installed outside a reaction vessel and includes a circular sidewall insulating part, a ceiling insulating part placed on the sidewall insulating part, and a heating element installed inside the sidewall insulating part. In addition, Patent document 2 discloses technology of forming a radial slit from the center of a ceiling plate of a vertical wafer boat toward the circumference of the ceiling plate so as to prevent problems caused by thermal deformation.    [Patent document 1] Japanese Unexamined Patent application Publication No. H8-55811    [Patent document 2] Japanese Unexamined Patent application Publication No. 2007-67232
However, cracks are easily generated in the insulating parts of the heating device, especially, in the ceiling insulating part of the heating device, and the cracks develop to break a ceiling part of the heating device breaks and drop the ceiling insulating part. However, in the related art, proper countermeasures against such cracks of the ceiling insulating part have not been studied.